So if this restaurant is touting fabulous underwater views, and the water outside is dark at the dinner hour, although in nearby Oslo, Norway the winters are dark early and long even if May-August should be spectacular, do they plan on hella lighting to make sure the hipsters are duly in awe of the super-special view?

How does this affect the life forms who didn’t sign up for this, and whose biological rhythms are now compromised? I beat up the interwebs but found very little on light pollution impacts to aquatic biota health, so instead, here:

Anyway, from an engineering standpoint not that challenging.
Besides, Norwegian engineers have decades of experience in building concrete structures in much tougher conditions, just look at all those concrete oil rigs Statoil put in the North Sea / Arctic Sea etc.
Those guys are good.